I don't know the Science paper
you refer to, but there have been a few studies on the spectra on natural
sounds:. The problem is the particular setting or corpus of sounds
surveyed will affect the results.

looked at classroom and offices, respectively, and generally found that
the spectrum of summed background sounds rolls off (declines in
amplitude) according to a 1/f function, somewhat similar to pink
noise.

However, in Gygi, B., Kidd, G. R. and Watson, C. S.
"Spectral-temporal factors in the identification of natural
sounds", to be published in JASA in Jan/Feb., I summed 100
environmental sounds and found that the long-term spectrum had slightly
less than a 1/f slope, possibly due to the inclusion of a
number of impact sounds that had high frequency transients.

the authors examined low-order statistics for speech, environmental
sounds and music gathered from samples on CD sound effects. They
found that the power spectra rolled off according to a modified power
law:

S(T)
=
1/(T02
+
T2)"/2

where
S(T)
is the amplitude of the spectrum at frequency
T,
"
ranges from 1.0-2.5, and
T0
specifies the f at which the rolloff begins. The
rolloff value is higher for speech than music or environmental
sounds. Note that the 1/f spectral rolloff mentioned above
is a special case of this general law.

I hope this helps.

Brian

At 06:29 PM 11/14/2003 +0000, Jan Schnupp wrote:

Dear List,

I have heard it said on a number of occasions that 1/f spectra are
very
commonly encountered among natural signals, and one might perhaps
expect
the auditory system to reflect this fact in its design
(perhaps the fact that auditory filters get wider at higher CF and
are
approximately logarithmically spaced is a simple relfection of the
1/f
nature of many sounds?)
However, I don't know ANY literature that discusses this 1/f phenomenon.
I
seem to remember somebody mentioning at a conference that there is
a
"classic" Science paper that marks the "discovery of the
1/f phenomenon".
If that is the case, I'd love to know the citation for it. Any
other
references for other (particularly recent!) work relating to 1/f and
it's
role in audition would of course also be very welcome. (Even better
would
be pdf files of relevant papers, if anyone has any).